The environmental benefits of managing plastic waste in this way are murky. PCX’s own analysis suggests there are very few emissions savings from the fuel switch, with most coming from those avoided in the transport of imported coal. It depends on cement factories’ pollution controls and the precise type of plastic being burnt, but the difference in CO2 emissions is “likely to be negligible,” said Ed Cook, a University of Leeds researcher who studies plastic waste.
In the sense that wood is; something you expect to end up in the atmosphere within a few centuries. And it has a fossil origin, so you’re on net adding to atmospheric CO2
Yeah, the fastest way to slow global warming is to keep it in the ground.